PR debug/77589

	PR debug/77589
include/
	* dwarf2.def (DW_OP_GNU_variable_value): New opcode.
gcc/
	* dwarf2out.c (struct dw_loc_list_struct): Add noted_variable_value
	bitfield.
	(size_of_loc_descr): Handle DW_OP_GNU_variable_value.
	(output_loc_operands): Handle DW_OP_call_ref and
	DW_OP_GNU_variable_value.
	(struct variable_value_struct): New type.
	(struct variable_value_hasher): Likewise.
	(variable_value_hash): New variable.
	(string_types): Remove.
	(copy_loc_descr): New function.
	(add_loc_descr_to_each): Clarify comment.  Use copy_loc_descr.
	(prepend_loc_descr_to_each): New function.
	(add_loc_list): Fix comment typo.  Use prepend_loc_descr_to_each
	instead of add_loc_descr_to_each if the first argument is single
	location list and the second has multiple.
	(resolve_args_picking_1): Handle DW_OP_GNU_variable_value.
	(loc_list_from_tree_1): For early_dwarf, emit DW_OP_GNU_variable_value
	when looking for variable value which doesn't have other location info.
	(loc_list_from_tree): Formatting fix.
	(gen_array_type_die): Simplify DW_AT_string_length handling.
	(adjust_string_types): Remove.
	(gen_subprogram_die): Don't call adjust_string_types nor test/set
	string_types.  Call resolve_variable_values.
	(prune_unused_types_walk_loc_descr): Handle DW_OP_GNU_variable_value.
	(resolve_addr_in_expr): Likewise.  Add A argument.
	(copy_deref_exprloc): Remove deref argument.  Adjust for the
	original expression being DW_OP_GNU_variable_value with optionally
	DW_OP_stack_value after it instead of DW_OP_call4 with DW_OP_deref
	optionally after it.
	(optimize_string_length): Rework for DW_OP_GNU_variable_value.
	(resolve_addr): Adjust optimize_string_length and resolve_addr_in_expr
	callers.  Set remove_AT_byte_size if removing DW_AT_string_length.
	(variable_value_hasher::hash, variable_value_hasher::equal): New
	methods.
	(resolve_variable_value_in_expr, resolve_variable_value,
	resolve_variable_values, note_variable_value_in_expr,
	note_variable_value): New functions.
	(dwarf2out_early_finish): Call note_variable_value on all toplevel
	DIEs.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@245733 138bc75d-0d04-0410-961f-82ee72b054a4